Sharing of bacterial strains between breast milk and infant feces

Area of Science:

• Microbiology
• Human Gut Microbiome
• Infant Health

Background:

• Human milk is recognized as a potential source of bacteria for the infant gut microbiome.
• Previous studies have suggested a link between maternal milk bacteria and infant gut colonization.

Purpose of the Study:

• To investigate the presence and identity of specific bacterial strains at the strain level in breast milk and infant fecal samples from mother-infant pairs.
• To confirm the transfer of bacterial strains from mother to infant via breastfeeding.

Main Methods:

• Bacterial DNA (Staphylococcus, Lactobacillus, Bifidobacterium) was detected using quantitative reverse transcription PCR (qRT-PCR).
• Bacterial isolates were cultured on various agar media and identified using classical tests combined with molecular techniques (PCR, RAPD, PFGE, MLST genotyping).
• Strain-level identification was performed on bacteria isolated from 20 mother-infant pairs.

Main Results:

• The same specific bacterial strains of Bifidobacterium, Lactobacillus, and Staphylococcus were found in both breast milk and infant fecal samples.
• Breast milk and infant feces from 19 out of 20 mother-infant pairs shared common bacterial species and strains.
• Two mother-infant pairs shared four bacterial strains, with most pairs sharing two.

Conclusions:

• The findings confirm the sharing of identical bacterial strains between breast milk and infant feces in mother-infant pairs.
• Breastfeeding is indicated as a significant contributor to the transfer of maternal bacteria to the infant gut.
• This transfer supports the colonization of the infant's gut microbiome by specific maternal bacterial strains.